RFR: 8306678: Replace use of os.version with an internal Version record [v5]

[Roger Riggs]

> Create an internal Version record to hold and compare versions of the form (major, minor, micro).
> Add `OperatingSystem.version()` to return the version of the running OS.
> Replace uses of os.version in java.base.
> Subsequent PRs will apply to uses in other modules including, jdk.jlink, jdk.jpackage, and java.desktop.

Roger Riggs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 28 commits:

 - Merge branch 'master' into 8306678-os-version
 - Merge branch '8304915-arch-enum' into 8306678-os-version
 - Correct comment on isPPC64() and refer to isLittleEndian() instead of mentioning PPC64LE
 - Simplify initialization in ClassLoaderHelper and fix VersionTest.
 - Revert changes to MacOsX sun.nio.fs.BsdFileStore; the version check is being removed in another PR.
 - Review comment updates
 - Simplify exception handling
 - Simplify version parsing
 - 8306678: Replace use of os.version with an internal Version record
 - Use and test of "s390" verified by reviewer.
 - ... and 18 more: https://git.openjdk.org/jdk/compare/f00a748b...1b5bd0f1

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Changes: https://git.openjdk.org/jdk/pull/13584/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13584&range=04
  Stats: 285 lines in 6 files changed: 268 ins; 10 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/13584.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13584/head:pull/13584

PR: https://git.openjdk.org/jdk/pull/13584